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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
Refrigerant High Pressure Switch
The refrigerant high pressure switch will stop the compressor if it trips. The refrigerant high
pressure switch is manual reset, therefore Fault 9 will occur when the compressor has
cooled after being stopped. Without intervention, the refrigerant high pressure switch will
remain open and therefore Fault 9 will re-occur after the system attempts to re-start.
Fault 9 Occurs 3 Consecutive Times
If Fault 9 occurs 3 consecutive times, the heat pump and element are disabled and no
further heating will occur. Cycling of the power supply will not reset this condition. For
instructions on how to reset Fault 9, refer to the Reset Button section on page 12.
The refrigerant high pressure switch is manual reset and may also need to be reset
following the occurrence of Fault 9.
The Freeze Protection function may be required whilst heating is disabled, refer to the
Freeze Protection section on page 17.
FREEZE PROTECTION
Whilst the Freeze Protection function is active, the green LED will display 4 flashes.
The Freeze Protection function is utilised in order to prevent the water within the heat
pump module freezing during low ambient conditions. (Only Series II heat pump models
are susceptible to freezing in the water circuit, due to the presence of a check valve in the
storage tank fittings).
If the compressor start delay has elapsed (it has been 45 minutes since the compressor
last ran) and the evaporator sensor temperature is less than 1°C for more than 15 minutes,
the circulator is switched on at full speed in order to circulate heated water from the
storage tank through the water circuit, to prevent freezing.
The circulator will switch off after 30 seconds.
The controller may utilise the Freeze Protection function when in any of the following
modes:
Standby Mode
System Check
Element Mode
– Ambient
Element Mode
– Fault
Fault 9
– Heating Disabled
Whilst the Freeze Protection function is active, the controller checks for Faults 1, 5 and 6
only.
